Rilmazafone (リスミー, Rhythmy, previously known as 450191-S) is a water-soluble prodrug developed in Japan. Once metabolized, rilmazafone is converted into several benzodiazepine metabolites that have sedative and hypnotic effects. These metabolites induce impairment of motor function and has hypnotic properties.
It is important to note that rilmazafone is not a benzodiazepine. It is therefore not regulated as such in several counties, including the United States. Rilmazafone has no effects on benzodiazepine receptors itself, nor does it produce any psychoactive effects prior to metabolism. However, once inside the body it is metabolized by aminopeptidase enzymes in the small intestine to form the principal active benzodiazepine 8-chloro-6-(2-chlorophenyl)-N,N-dimethyl-4H-1,2,4-triazolo [1,5-a][1,4]benzodiazepine-2-carboxamide. As can be seen in the molecular diagram below, the principal metabolite contains a benzodiazepine ring structure (i.e., a benzene ring fused with a diazepine ring), unlike the parent compound (rilmazafone), which has no diazepine ring.
The active metabolite is Rilmazolam